FORMATION OF THE SHORT-LIVED RADIONUCLIDE {sup 36}Cl IN THE PROTOPLANETARY DISK DURING LATE-STAGE IRRADIATION OF A VOLATILE-RICH RESERVOIR

Journal Article · Wed Apr 20 00:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/731/2/L28· OSTI ID:21562732

Jacobsen, Benjamin; Qingzhu, Yin ^[1]; Matzel, Jennifer; Hutcheon, Ian D; Ramon, Erick C; Weber, Peter K ^[2]; Krot, Alexander N; Nagashima, Kazuhide ^[3]; Ishii, Hope A ^[4]

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1. Department of Geology, University of California, Davis, CA 95616 (United States)
2. Glenn T. Seaborg Institute, Chemical Science Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)
3. School of Ocean, Earth Science and Technology, Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa, Honolulu, HI 96822 (United States)
4. Institute for Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

Short-lived radionuclides (SLRs) in the early solar system provide fundamental insight into protoplanetary disk evolution. We measured the {sup 36}Cl-{sup 36}S-isotope abundance in wadalite (<15 {mu}m), a secondary chlorine-bearing mineral found in calcium-aluminum-rich inclusions (CAIs) in the Allende CV chondrite, to decipher the origin of the SLR {sup 36}Cl ({tau}{sub 1/2} {approx} 3 x 10{sup 5} yr) in the early solar system. Its presence, initial abundance, and the noticeable decoupling from {sup 26}Al raise serious questions about the origin of SLRs. The inferred initial {sup 36}Cl abundance for wadalite, corresponding to a {sup 36}Cl/{sup 35}Cl ratio of (1.81 {+-} 0.13) x 10{sup -5}, is the highest {sup 36}Cl abundance ever reported in any early solar system material. The high level of {sup 36}Cl in wadalite and the absence of {sup 26}Al ({sup 26}Al/{sup 27}Al {<=} 3.9 x 10{sup -6}) in co-existing grossular (1) unequivocally support the production of {sup 36}Cl by late-stage solar energetic particle irradiation in the protoplanetary disk and (2) indicates that the production of {sup 36}Cl, recorded by wadalite, is unrelated to the origin of {sup 26}Al and other SLRs ({sup 10}Be, {sup 53}Mn) recorded by primary minerals of CAIs and chondrules. We infer that {sup 36}Cl was largely produced by irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the region in which the CV chondrite parent asteroid accreted while the Sun was a weak T Tauri star. Subsequently, {sup 36}Cl accreted into the Allende CV chondrite together with condensed water ices.

• OSTI ID: 21562732
• Journal Information: Astrophysical Journal Letters, Vol. 731, Issue 2; Other Information: DOI: 10.1088/2041-8205/731/2/L28; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ALUMINIUM 26
ALUMINIUM 27
BERYLLIUM 10
CHLORINE 35
CHLORINE 36
CHONDRITES
DECOUPLING
ELEMENT ABUNDANCE
EVOLUTION
MANGANESE 53
PROTOPLANETS
SOLAR SYSTEM
T TAURI STARS
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ALKALINE EARTH ISOTOPES
ALUMINIUM ISOTOPES
BERYLLIUM ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BINARY STARS
CHLORINE ISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ERUPTIVE VARIABLE STARS
EVEN-EVEN NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
MANGANESE ISOTOPES
METEORITES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
STABLE ISOTOPES
STARS
STONE METEORITES
VARIABLE STARS
YEARS LIVING RADIOISOTOPES